But President Jacques Chirac's hand will be pictured by many behind the back of his long-time servant and ally, compounding the president's reputation as a reckless political dice-roller and determined escapologist.
Mr Juppe's decision is politically unprecedented and constitutionally extremely doubtful. His departure may be enough to tip the second round towards the centre-right but there could also be a reaction against what will be seen as a cynical manouevre.
President Chirac's decision to call a snap election already pushed the constitution of the Fifth Republic to its limit. The ditching of a prime minister between rounds of a parliamentary election strains the bounds of presidential propriety.
Will it succeed? It may. Mr Juppe, leader of Mr Chirac's party, the Gaullist RPR, was the second least popular prime minister in recent history. The prospect that President Chirac might appoint a more consensual and charismatic figure - possibly the outgoing parliamentary president, Phillippe Seguin - could persuade many disaffected centre-right voters to turn out in the second round on Sunday.
But the appalling first round score of the RPR and its allies the UDF - at 31 per cent, the worst by the centre right in 40 years - was also a rebuff for Mr Chirac and Chiraquism. It was the President, as much as Mr Juppe, who failed to deliver on his promises of two years ago to cut unemployment and heal France's "social fractures". It was the President who took the decision to call the election nine months early. It was the President's RPR party which endured some of the most stinging reverses on Sunday night.
In the President's one-time unassailable fortress, the city of Paris, the centre-right may lose six seats, including that of Mr Chirac's long- time friend and successor as Mayor, Jean Tiberi.
To protect the last five years of his presidency from cohabitation with a left-wing government, the President is expected to make another personal intervention before Sunday - probably in a television address on Thursday or Friday evening. What remains of constitutional etiquette will prevent him from naming Mr Juppe's potential successor. But leaks may fill the gap.
Will it be semi-dissident Mr Seguin of the RPR, a man who has recently curbed his EMU-scepticism? Or will it be the rising force in the UDF, the education minister, Francois Bayrou? Sources within the RPR say Mr Chirac would be extremely unwilling to appoint either man since the post might provide a springboard for them to challenge him for the presidency in 2002. A reconciliation with Mr Chirac's old friend, Edouard Balladur, who unsuccessfully used the premiership to try to do just that in 1995, is regarded as out of the question.
The great personal victor of the first round is undoubtedly the Socialist leader, Lionel Jospin. Whatever the outcome this weekend, he is now established as the clear master of the French left.
Sunday's vote re-established the Socialists, with 25.5 per cent, as the most popular single party in France. The loose alliance of Socialists, Communists and Greens, together with minority leftish parties, scored 44.3 per cent in the first round. This could provide the platform for a narrow win by the left on Sunday. But Mr Jospin has few political reserves to call on.
The non-vote on Sunday - including spoiled ballots a near-record 35 per cent - is believed to be disproportionately on the centre-right. Mr Jospin's hopes depend, with dark irony, on the behaviour of the first-round voters of the far-right National Front. In those constituencies where the NF candidate has been eliminated, the far-right votes, on past form, should transfer to the centre-right.
The left's chances of forming a majority depend on winning many of the 78 seats, out of 577, in which the right-wing vote will be split by a three-cornered fight between the left, the centre-right and the NF. It seems the left's chances of winning these seats is good. But to have a real chance of power, Mr Jospin probably needed perhaps 100 or 150 three-way battles.Reuse content